A new approach for evaluating clipping distortion in multicarrier systems

Bahai, A.; Singh, Mohit Kumar; Goldsmith, Andrea; Saltzberg, B.R.

doi:10.1109/jsac.2002.1007384

Cited by 107 publications

(43 citation statements)

References 23 publications

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“…We now treat as a complex Gaussian random variable. Then and are fully determined by from (23). We denote these relationships using the two functions below:…”

Section: G Efficient Techniques To Evaluate the Conditional Means Anmentioning

confidence: 99%

Superposition Coded Modulation With Peak-Power Limitation

Tong

Ping

2009

IEEE Trans. Inform. Theory

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Abstract-We apply clipping to superposition coded modulation (SCM) systems to reduce the peak-to-average power ratio (PAPR) of the transmitted signal. The impact on performance is investigated by evaluating the mutual information driven by the induced peak-power-limited input signals. It is shown that the rate loss is marginal for moderate clipping thresholds if optimal encoding/decoding is used. This fact is confirmed in examples where capacityapproaching component codes are used together with the maximum a posteriori probability (MAP) detection. In order to reduce the detection complexity of SCM with a large number of layers, we develop a suboptimal soft compensation (SC) method that is combined with soft-input soft-output (SISO) decoding algorithms in an iterative manner. A variety of simulation results for additive white Gaussian noise (AWGN) and fading channels are presented. It is shown that with the proposed method, the effect of clipping can be efficiently compensated and a good tradeoff between PAPR and bit-error rate (BER) can be achieved. Comparisons with other coded modulation schemes demonstrate that SCM offers significant advantages for high-rate transmissions over fading channels.

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“…We now treat as a complex Gaussian random variable. Then and are fully determined by from (23). We denote these relationships using the two functions below:…”

Section: G Efficient Techniques To Evaluate the Conditional Means Anmentioning

confidence: 99%

Superposition Coded Modulation With Peak-Power Limitation

Tong

Ping

2009

IEEE Trans. Inform. Theory

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“…Second, since the OFDM signals with high peak power occur less frequently than those with low peak power [16], the event that the OFDM signal is affected by nonlinear distortion becomes rare [30], especially in the high-SDR region where the IBO is set high.…”

Section: Error Vector Magnitudementioning

confidence: 99%

Characterization of power spectral density for nonlinearly amplified OFDM signals based on cross-correlation coefficient

Lee

Ochiai

2014

J Wireless Com Network

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Orthogonal frequency division multiplexing (OFDM) has been adopted in many modern communication systems due to its robustness against frequency-selective fading channels as well as its near-rectangular spectrum that can achieve high spectral efficiency. However, its major drawback is the resulting signal with high peak-to-average power ratio (PAPR), which causes severe nonlinear distortion at the power amplifier (PA) unless input backoff is chosen sufficiently large. The effect of the nonlinear distortion is two-fold: out-of-band radiation and signal quality degradation. The former causes adjacent channel interference and thus degrades the bandwidth efficiency. The latter affects the system level performance and is often measured by the error vector magnitude (EVM). It is thus important for the system designer to analyze the nonlinear distortion caused by a given PA in terms of power spectral density (PSD) and EVM, but accurate calculation of these characteristics may be generally involved. In this work, by establishing the link between the cross-correlation coefficient of the input and output signals from PA and the resulting PSD, we characterize the in-band and out-of-band distortion of nonlinearly amplified OFDM signals based exclusively on the cross-correlation coefficient. The accuracy of the proposed approach is confirmed by both simulation and measurement using a real PA.

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“…If such resulting signals are transmitted through non-linear high power amplifiers (HPA), as the ones used in satellite and mobile phones, the high amplitude peaks will be compressed or even clipped by the amplifier, leading to intermodulation, high outof-band emission (OOBE) and performance loss due to the intercarrier interference (ICI) [12]. ICI can cause prohibitive degradation of the symbol error rate (SER) performance and increases adjacent channel interference [13]. Incrementing the input power back-off (IBO) reduces the non-linear distortions, but also reduces the amplifier power efficiency, which clearly cannot be applied to energy-limited devices [14].…”

Section: Introductionmentioning

confidence: 99%

PAPR Reduction and Performance Improvement in OFDM Systems using WHT-based Schemes

Aquino¹,

Mendes²

2017

JCIS

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Abstract-Orthogonal frequency division multiplexing (OFDM) is a robust and reliable multicarrier modulation scheme that has proven to be adequate for broadband communications. It is widely used in broadcasting and broadband wireless and wireline systems. However, in scenarios where the communication devices are power-limited, such as mobile and satellite communications, OFDM has not been massively used or even not used at all. For instance, OFDM is used only in downlink of 4G networks, while the uplink uses single carrier frequency division multiplexing. One of the main culprits of this is the high peak to average power ratio (PAPR) of the OFDM signal. Reducing the PAPR of the OFDM signals is important for a large variety of application. Several PAPR reduction techniques for OFDM have been proposed recently. The aim of this paper is to present a tutorial about a set of algorithms based on Walsh-Hadamard transform (WHT) for reducing the PAPR of the OFDM symbols. We also propose a new technique, named selective mapping based on WHT without extended information (SLM-WHT-WEI), which does not convey the explicit information to the receiver. We will show that the approaches based on WHT can also improve the OFDM symbol error rate performance over frequency-selective channels. Different schemes based on the properties of the WHT are presented and compared, assuming linear and non-linear channels. The PAPR reduction performance analysis shows that the PAPR can be effectively reduced while good performance in terms of symbol error rate can be achieved even in severely constrained channel conditions.

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A new approach for evaluating clipping distortion in multicarrier systems

Cited by 107 publications

References 23 publications

Superposition Coded Modulation With Peak-Power Limitation

Superposition Coded Modulation With Peak-Power Limitation

Characterization of power spectral density for nonlinearly amplified OFDM signals based on cross-correlation coefficient

PAPR Reduction and Performance Improvement in OFDM Systems using WHT-based Schemes

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